Spring Property Overriding Demo

This Spring Boot application is a sample project specifically designed to demonstrate property overriding behavior in a Spring Boot configuration.

Purpose

The purpose of this application is to show the specifics of the properties overriding mechanism in a Spring Boot project.

Structure

• ApplicationPropertiesHolder class maps its fields to corresponding properties to be loaded from different property sources. The expectation is, while each property/field is defined in either application.properties or app.properties, both should be overridden by same-name values in override.properties.
• AdditionalConfigurationFilesAdder class adds additional property sources to the application's environment. The added sources will override values defined in application.properties including profile-specific application-*.properties.
• Application class serves as the entry point of the application.

Usage

To run the project, follow these steps:

1. Ensure that you have Java and Maven installed on your system.
2. Clone the repository and navigate to the project directory.
3. Build the project using the command: mvn clean install
4. Run the application using the command: mvn test

Properties Files Used

• application.properties: defines the application field in the ApplicationPropertiesHolder class.
• app.properties: defines the app field in the ApplicationPropertiesHolder class.
• override.properties: overrides both app and application properties.

Tests

The PropertiesConfigTest class includes two test methods:

• definedInAppProperties(): verifies that the value of the app
• property is overridden as expected according to override.properties.
• definedInApplicationProperties(): asserts that the value of the
• application property is overridden according to override.properties.

Links

The specifics of Spring Boot property overriding behavior discussed on GitHub and on StackOverflow:

• @PropertySource not overriding in order [SPR-13500] - in a comment by Maksim Muruev (mmuruev).
• How to override application.properties during production in Spring-Boot? - in a comment by Alexander Vasiljev.
• @PropertySource doesn't override properties defined in application.properties - My question and an answer to it that helped to build this solution. Thanks to M. Deinum from Netherlands